root/jmemmac.c
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DEFINITIONS
This source file includes following definitions.
- GLOBAL
- jpeg_free_small
- GLOBAL
- jpeg_free_large
- jpeg_mem_available
- METHODDEF
- METHODDEF
- METHODDEF
- jpeg_open_backing_store
- jpeg_mem_init
- jpeg_mem_term
/*
* jmemmac.c
*
* Copyright (C) 1992-1997, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
* jmemmac.c provides an Apple Macintosh implementation of the system-
* dependent portion of the JPEG memory manager.
*
* If you use jmemmac.c, then you must define USE_MAC_MEMMGR in the
* JPEG_INTERNALS part of jconfig.h.
*
* jmemmac.c uses the Macintosh toolbox routines NewPtr and DisposePtr
* instead of malloc and free. It accurately determines the amount of
* memory available by using CompactMem. Notice that if left to its
* own devices, this code can chew up all available space in the
* application's zone, with the exception of the rather small "slop"
* factor computed in jpeg_mem_available(). The application can ensure
* that more space is left over by reducing max_memory_to_use.
*
* Large images are swapped to disk using temporary files and System 7.0+'s
* temporary folder functionality.
*
* Note that jmemmac.c depends on two features of MacOS that were first
* introduced in System 7: FindFolder and the FSSpec-based calls.
* If your application uses jmemmac.c and is run under System 6 or earlier,
* and the jpeg library decides it needs a temporary file, it will abort,
* printing error messages about requiring System 7. (If no temporary files
* are created, it will run fine.)
*
* If you want to use jmemmac.c in an application that might be used with
* System 6 or earlier, then you should remove dependencies on FindFolder
* and the FSSpec calls. You will need to replace FindFolder with some
* other mechanism for finding a place to put temporary files, and you
* should replace the FSSpec calls with their HFS equivalents:
*
* FSpDelete -> HDelete
* FSpGetFInfo -> HGetFInfo
* FSpCreate -> HCreate
* FSpOpenDF -> HOpen *** Note: not HOpenDF ***
* FSMakeFSSpec -> (fill in spec by hand.)
*
* (Use HOpen instead of HOpenDF. HOpen is just a glue-interface to PBHOpen,
* which is on all HFS macs. HOpenDF is a System 7 addition which avoids the
* ages-old problem of names starting with a period.)
*
* Contributed by Sam Bushell (jsam@iagu.on.net) and
* Dan Gildor (gyld@in-touch.com).
*/
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "jmemsys.h" /* import the system-dependent declarations */
#ifndef USE_MAC_MEMMGR /* make sure user got configuration right */
You forgot to define USE_MAC_MEMMGR in jconfig.h. /* deliberate syntax error */
#endif
#include <Memory.h> /* we use the MacOS memory manager */
#include <Files.h> /* we use the MacOS File stuff */
#include <Folders.h> /* we use the MacOS HFS stuff */
#include <Script.h> /* for smSystemScript */
#include <Gestalt.h> /* we use Gestalt to test for specific functionality */
#ifndef TEMP_FILE_NAME /* can override from jconfig.h or Makefile */
#define TEMP_FILE_NAME "JPG%03d.TMP"
#endif
static int next_file_num; /* to distinguish among several temp files */
/*
* Memory allocation and freeing are controlled by the MacOS library
* routines NewPtr() and DisposePtr(), which allocate fixed-address
* storage. Unfortunately, the IJG library isn't smart enough to cope
* with relocatable storage.
*/
GLOBAL(void *)
jpeg_get_small (j_common_ptr cinfo, size_t sizeofobject)
{
return (void *) NewPtr(sizeofobject);
}
void
jpeg_free_small (j_common_ptr cinfo, void * object, size_t sizeofobject)
{
DisposePtr((Ptr) object);
}
/*
* "Large" objects are treated the same as "small" ones.
* NB: we include FAR keywords in the routine declarations simply for
* consistency with the rest of the IJG code; FAR should expand to empty
* on rational architectures like the Mac.
*/
GLOBAL(void FAR *)
jpeg_get_large (j_common_ptr cinfo, size_t sizeofobject)
{
return (void FAR *) NewPtr(sizeofobject);
}
void
jpeg_free_large (j_common_ptr cinfo, void FAR * object, size_t sizeofobject)
{
DisposePtr((Ptr) object);
}
/*
* This routine computes the total memory space available for allocation.
*/
long
jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed,
long max_bytes_needed, long already_allocated)
{
long limit = cinfo->mem->max_memory_to_use - already_allocated;
long slop, mem;
/* Don't ask for more than what application has told us we may use */
if (max_bytes_needed > limit && limit > 0)
max_bytes_needed = limit;
/* Find whether there's a big enough free block in the heap.
* CompactMem tries to create a contiguous block of the requested size,
* and then returns the size of the largest free block (which could be
* much more or much less than we asked for).
* We add some slop to ensure we don't use up all available memory.
*/
slop = max_bytes_needed / 16 + 32768L;
mem = CompactMem(max_bytes_needed + slop) - slop;
if (mem < 0)
mem = 0; /* sigh, couldn't even get the slop */
/* Don't take more than the application says we can have */
if (mem > limit && limit > 0)
mem = limit;
return mem;
}
/*
* Backing store (temporary file) management.
* Backing store objects are only used when the value returned by
* jpeg_mem_available is less than the total space needed. You can dispense
* with these routines if you have plenty of virtual memory; see jmemnobs.c.
*/
METHODDEF(void)
read_backing_store (j_common_ptr cinfo, backing_store_ptr info,
void FAR * buffer_address,
long file_offset, long byte_count)
{
long bytes = byte_count;
long retVal;
if ( SetFPos ( info->temp_file, fsFromStart, file_offset ) != noErr )
ERREXIT(cinfo, JERR_TFILE_SEEK);
retVal = FSRead ( info->temp_file, &bytes,
(unsigned char *) buffer_address );
if ( retVal != noErr || bytes != byte_count )
ERREXIT(cinfo, JERR_TFILE_READ);
}
METHODDEF(void)
write_backing_store (j_common_ptr cinfo, backing_store_ptr info,
void FAR * buffer_address,
long file_offset, long byte_count)
{
long bytes = byte_count;
long retVal;
if ( SetFPos ( info->temp_file, fsFromStart, file_offset ) != noErr )
ERREXIT(cinfo, JERR_TFILE_SEEK);
retVal = FSWrite ( info->temp_file, &bytes,
(unsigned char *) buffer_address );
if ( retVal != noErr || bytes != byte_count )
ERREXIT(cinfo, JERR_TFILE_WRITE);
}
METHODDEF(void)
close_backing_store (j_common_ptr cinfo, backing_store_ptr info)
{
FSClose ( info->temp_file );
FSpDelete ( &(info->tempSpec) );
}
/*
* Initial opening of a backing-store object.
*
* This version uses FindFolder to find the Temporary Items folder,
* and puts the temporary file in there.
*/
void
jpeg_open_backing_store (j_common_ptr cinfo, backing_store_ptr info,
long total_bytes_needed)
{
short tmpRef, vRefNum;
long dirID;
FInfo finderInfo;
FSSpec theSpec;
Str255 fName;
OSErr osErr;
long gestaltResponse = 0;
/* Check that FSSpec calls are available. */
osErr = Gestalt( gestaltFSAttr, &gestaltResponse );
if ( ( osErr != noErr )
|| !( gestaltResponse & (1<<gestaltHasFSSpecCalls) ) )
ERREXITS(cinfo, JERR_TFILE_CREATE, "- System 7.0 or later required");
/* TO DO: add a proper error message to jerror.h. */
/* Check that FindFolder is available. */
osErr = Gestalt( gestaltFindFolderAttr, &gestaltResponse );
if ( ( osErr != noErr )
|| !( gestaltResponse & (1<<gestaltFindFolderPresent) ) )
ERREXITS(cinfo, JERR_TFILE_CREATE, "- System 7.0 or later required.");
/* TO DO: add a proper error message to jerror.h. */
osErr = FindFolder ( kOnSystemDisk, kTemporaryFolderType, kCreateFolder,
&vRefNum, &dirID );
if ( osErr != noErr )
ERREXITS(cinfo, JERR_TFILE_CREATE, "- temporary items folder unavailable");
/* TO DO: Try putting the temp files somewhere else. */
/* Keep generating file names till we find one that's not in use */
for (;;) {
next_file_num++; /* advance counter */
sprintf(info->temp_name, TEMP_FILE_NAME, next_file_num);
strcpy ( (Ptr)fName+1, info->temp_name );
*fName = strlen (info->temp_name);
osErr = FSMakeFSSpec ( vRefNum, dirID, fName, &theSpec );
if ( (osErr = FSpGetFInfo ( &theSpec, &finderInfo ) ) != noErr )
break;
}
osErr = FSpCreate ( &theSpec, '????', '????', smSystemScript );
if ( osErr != noErr )
ERREXITS(cinfo, JERR_TFILE_CREATE, info->temp_name);
osErr = FSpOpenDF ( &theSpec, fsRdWrPerm, &(info->temp_file) );
if ( osErr != noErr )
ERREXITS(cinfo, JERR_TFILE_CREATE, info->temp_name);
info->tempSpec = theSpec;
info->read_backing_store = read_backing_store;
info->write_backing_store = write_backing_store;
info->close_backing_store = close_backing_store;
TRACEMSS(cinfo, 1, JTRC_TFILE_OPEN, info->temp_name);
}
/*
* These routines take care of any system-dependent initialization and
* cleanup required.
*/
long
jpeg_mem_init (j_common_ptr cinfo)
{
next_file_num = 0;
/* max_memory_to_use will be initialized to FreeMem()'s result;
* the calling application might later reduce it, for example
* to leave room to invoke multiple JPEG objects.
* Note that FreeMem returns the total number of free bytes;
* it may not be possible to allocate a single block of this size.
*/
return FreeMem();
}
void
jpeg_mem_term (j_common_ptr cinfo)
{
/* no work */
}